'No Such File or Directory" Error When Working with Shared File
No such file or directory" is somewhat common when 


the file needs something else to be processed by the software you are working with (missing shared library for blender, missing linked file with textures, materials...)
the file doesn't exist (or at least it doesn't exist in the given directory)
the filename or the path consists of characters that cannot be read by linux


I assume that you have already used blender on linux successfully (eg opened a local file), so the first point is not the cause of the problem.

Permissions between operating systems are not as easy as it sounds. Both Apple and Windows tend to use some "magic" in their approaches of an easy-sounding task. So it's good to verify the permissions on OS level. 

Try the following: Navigate to the tiger.blend file by using either the file browser (dolphin for KDE, Nautilus for GNOME, for Ubuntu whatever they are using) or the command line and try to rename the file into tiger1.blend. If you are able to successfully rename the file then there are no permission problems on the OS level. 

Last but not least Blender does not necessarily use all of the Desktop Environment's file selection methods. While KDE's dolphin is capable of browsing paths with blanks (something like //Macbook/Awesome Blender Files/tiger.blend) other file managers might not. Blender seems to process blanks in paths correctly on SMB (samba) and CIFS (common internet file system) shares but I've never tried using Mac OS as a host system. Try to use simple paths without blanks, accents, umlauts, special characters...